I had this same thing happen to me a couple months ago,and after endless searching and wire tracing,I ended up wiring in a push button like IDIBRONCO and riphip recommended.I like the simplicity of it,and not having to worry about those stupid actuators.I wired in a fuse block under the hood for other accessories,so I just ran a wire from a terminal on the fuse block,to the push button switch on the dash,then back to the small terminal on the starter solenoid,then she fired right up and hasn't given me a problem since.Electrical can definetly be frustrating at times but once you know the basics and feel comfortable doing it,you will begin to enjoy wiring stuff.You have it right with the multimeter,just make sure you get a decent meter.
Rock